Necking

About: Necking is a research topic. Over the lifetime, 5280 publications have been published within this topic receiving 113945 citations.

Material Instabilities in Solids

Abstract: Introduction to Material Instabilities in Solids (E. van der Giessen & R. de Borst). Stability of Layered Geological Structures: An Asymptotic Solution (Y. Leroy & N. Triantafyllidis). Analysis of Shear Failure in Concrete Materials (K. William, et al.). On the Effects of Inertial Coupling on the Wave-Speeds of Elastic-Plastic Fluid-Saturated Porous Media (B. Loret & E. Rizzi). Microstructured Solids: Non-Linear Model and Analysis of Magneto-Elastic Wave Processes (V. Erofeyev & S. Kovalev). Thermodynamics of Crystal Viscoplasticity and Instability Phenomena (P. Perzyna). Instability Issues in Single Crystal Plasticity (P. Steinmann). On the Use of Strain-Softening Models for the Simulation of Strong Discontinuities in Solids (J. Oliver, et al.). Thermomechanics Based Theory and Analysis of Cracking Localization in Concrete Dam under Earthquake Excitation (H. Horii, et al.). Localisation Patterns in Ductile and Brittle Geomaterials (J. Desrues).In-Plane Crushing of a Polymeric Honeycomb (S. Papka & S. Kyriakides). Experimental and Numerical Investigation of Size Scale Effects in Concrete Fracture (M. van Vliet & J. van Mier). Post-Peak Behaviour of Rocks and Natural Building Stones in Uniaxial Compression (I. Vardoulakis, et al.). Inelastic Deformation of F.C.C. Single Crystals by Slip and Twinning (A. Staroselsky & L. Anand). Effects of Strain Paths on Sheet Metal Limit Strains (P. Wu, et al.). Three-Dimensional Analysis of Localized Necking (A. Benallal). Effects of Heterogeneities and Localization on Polymer Deformation and Recovery (M. Boyce & C. Chui). Strain Localization and Void Growth in Polymers (A. Steenbrink & E. van der Giessen). Nonaffine Network Model for Glassy Polymer and Prediction of Instability Propagation (Y. Tomita & T. Adachi). Damage Localisation in Short Fibre Cementitious Composites (B. Karihaloo & J. Wang). Fracture Instabilities in Heterogeneous Materials: Brittleness, Size Effects and Fractality (A. Carpinteri). Compression Fracture-Mechanics of Damage Localization and Size Effect (Z. Bazant). Nonlinear Modelling of Geomaterials and Self-Organization Phenomena (V. Nikolaevskiy). Quasi-Static and Dynamic Characteristics of Strain Gradient Dependent Non-Local Constitutive Models (F. Oka, et al.). Higher-Order Damage Models for the Analysis of Fracture in Quasi-Brittle Materials (M. Geers, et al.). On Gradient Regularization for Numerical Analyses in the Presence of Damage (C. Comi & L. Driemeier). Localisation of Damage in Quasi-Brittle Materials and Influence of Chemically Activated Damage (G. Pijaudier-Cabot, et al.). Nonlocal Damage Effects on Plastic Flow Localization under Dynamic Loading (V. Tvergaard & A. Needleman). Instabilities and Size Effects in Plasticity: Continuum and Dislocation Approaches (H. Zbib). Macroscopic Modelling of Stationary and Propagative Instabilities (L. Sluys & W. Wang). A Discussion of Strain Gradient Plasticity Theories and Application to Shear Bands (N. Fleck & J. Hutchinson). A Beam Theory for Gradient Continua (H.-B. Muhlhaus & P. Hornby). Recent Progress on Gradient Theory and Applications (E. Aifantis). Index.

Thickness dependence of cracking resistance in thin aluminium plates

Abstract: The influence of thickness on the fracture toughness of aluminium 6082T0 thin plates of 1-6 mm thicknesses was investigated experimentally and numerically from tensile testing of cracked DENT specimens. The critical J-integral, J(c), critical CTOD, delta(CTODc), and essential work of fracture, w(e), are found to increase with thickness and to constitute equivalent measures of fracture toughness at small thickness. For larger thickness, J(c) and delta(CTODc) increase non-linearly with thickness and reach a maximum for 5-6 mm thickness Whereas iv, keeps increasing linearly with thickness. This difference is related to a more progressive development of the necking zone in front of the crack tip when thickness increases: at large thickness, cracking initiates well before the neck has developed to its stationary value during propagation, w(e) is more directly related to the steady-state crack growth resistance. A linear regression on the fracture toughness/thickness curve allows further separation of the two contributions of the essential work of fracture: the necking work and the fracture work spent for damaging. The maximum of the stress triaxiality ratio is shown to constitute a pertinent parameter for characterising how constraint affects cracking initiation in the present context where out-of-plane constraint dominates in-plane constraint. It allows justifying the shape of the J(c)/thickness relationship and results in the proposal of a 3D J(c)/thickness/triaxiality fracture locus. As fracture profiles are macroscopically flat with microscopic dimples and with only very small shear lips along the edges, a local criterion based on the growth and coalescence of voids has been used in order to predict fracture initiation. (C) 1999 Elsevier Science Ltd. All rights reserved.

Droplet formation in microfluidic T-junction generators operating in the transitional regime. II. Modeling.

Abstract: This is the second part of a two-part study on the generation of droplets at a microfluidic T-junction operating in the transition regime. In the preceding paper [Phys. Rev. E 85, 016322 (2012)], we presented our experimental observations of droplet formation and decomposed the process into three sequential stages defined as the lag, filling, and necking stages. Here we develop a model that describes the performance of microfluidic T-junction generators working in the squeezing to transition regimes where confinement of the droplet dominates the formation process. The model incorporates a detailed geometric description of the drop shape during the formation process combined with a force balance and necking criteria to define the droplet size, production rate, and spacing. The model inherently captures the influence of the intersection geometry, including the channel width ratio and height-to-width ratio, capillary number, and flow ratio, on the performance of the generator. The model is validated by comparing it to speed videos of the formation process for several T-junction geometries across a range of capillary numbers and viscosity ratios.